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Giant Adrenal Oncocytoma: A Case Report and Literature Review
Kohei Yamakawa1, Akihiro Ono1, Ryo Amakawa1
1Department of Urology NTT Medical Center Tokyo Tokyo Japan.
Introduction:
Adrenal oncocytomas are rare, nonfunctioning tumors composed of eosinophilic oncocytic cells whose nonspecific imaging often impedes preoperative diagnosis. We report a case of a large nonfunctioning adrenal oncocytoma with borderline malignant potential, incidentally discovered during cardiac symptom evaluation.
Case Presentation:
A 77-year-old man with an incidentally discovered retroperitoneal tumor was referred to Urology for further evaluation. Contrast-enhanced CT revealed a 93-mm lobulated mass with heterogeneous enhancement abutting the left kidney's upper pole. Given the tumor's size, open left nephrectomy and adrenalectomy were performed. Gross and histopathology revealed a yellowish, solid adrenal tumor composed predominantly of oncocytic cells with no invasion of the kidney. Immunohistochemistry revealed a low Ki-67 index (approximately 2%). The tumor was classified as having borderline malignant potential (Lin-Weiss-Bisceglia criteria).
Conclusion:
We present a rare case of nonfunctioning adrenal oncocytoma with borderline malignant potential. Long-term follow-up is recommended due to the uncertain malignant potential.
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